Taking a PowerWalk

Soldiers on Foot Generate Their Own Energy With Bionic Brace

Nov. 25, 2012 - 03:51PM
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VICTORIA, British Columbia — Soldiers faced with carrying too many heavy batteries needed to run their equipment could be getting a lightweight mechanical knee brace that generates power while they’re on the move.

Bionic Power of Burnaby, British Columbia, has developed what it is calling the PowerWalk system. The device resembles an athletic knee brace and uses principles similar to regenerative braking in hybrid cars to generate electricity from the natural motion of walking and then use it to charge a wide range of portable battery-powered devices, said Yad Garcha, the company’s CEO.

PowerWalk weighs about 750 grams (1.7 pounds) per leg, and with a device on each leg, a user walking at a comfortable speed generates an average of 12 watts of electricity. At that rate, a little over one hour of walking generates enough electricity to fully charge four mobile phones.

In September, Bionic Power announced it had received three military contracts to conduct further work on its PowerWalk system.

Garcha declined to discuss the value of the contracts, saying he wanted to limit the amount of public information for competitive reasons. But two of the contracts — one from the U.S. Army and one from Canada’sDepartment of National Defence — are designed to further refine the PowerWalk system for military use. The third contract is from the U.S. Defense Advanced Research Projects Agency (DARPA).

“With the Canadian contract, we are trying to improve the algorithm so we are more helpful to the soldier carrying weight, particularly going downhill, and perhaps produce more power,” Garcha said.

Assistive harvesting makes it easier for users to walk downhill, reducing muscle fatigue and potentially decreasing the incidence of injury.

“With the U.S., we are looking at re-engineering the gear box to make it significantly smaller than what it currently is,” Garcha said. “And we’re also improving the ergonomics so it’s more comfortable to wear.”

The U.S. Army contract, awarded through the Natick Soldier Research, Development and Engineering Center, is supported by the U.S. Army Project Manager Soldier Warrior.

The Canadian funding comes through Defence Research and Development Canada (DRDC), the Canadian Forces’ science agency.

Bionic Power is collaborating with robotics company Boston Dynamics on a DARPA program called Warrior Web, aimed at preventing and reducingmusculoskeletal injuries.

Garcha said that is being funded to research how technology can help capture some of the energy created during walking to assist the soldier in carrying heavy loads.

“Let’s say if you’re walking and you capture some power — rather than turning it into electricity, you could store it in hydraulic fluid, for instance, or in some kind of spring,” Garcha said. “And when you need it, you release it, so you’re capturing and releasing in the same stride.”

Garcha said the company expects to deliver a refined PowerWalk device to the U.S. Army and DRDC next year. The DARPA initiative covers a longer period, he said.

Once that product is delivered and tested, the firm will have to determine how to build it to meet military specifications. Then comes manufacturing.

The initial device went through early testing by the Canadian Forces in 2008, but that was limited to having soldiers walk around wearing the system.

Still, the Canadian Forces felt the results were strong enough to warrant further studies. At the time, Robert Walker, then head of DRDC, said Bionic Power was “leading the world” in what he called human-energy harvesting.

Garcha said more extensive tests are needed, during which soldiers will conduct a 72-hour mission wearing the refined PowerWalk device. Testing will determine how much power is produced regular ly and also how many fewer batteries a soldier has to carry in the field.

“That’s the real test,” Garcha said. “Can we reduce the disposable battery consumption in the field and reduce the weight the soldier is carrying?”

Another Promising Development

Canadian soldiers carry 13 to 15 batteries to operate their portable devices. These batteries can weigh as much as 5 kilograms, according to the Canadian military.

Canada’s Department of National Defence has also brought in Rheinmetall Canada to deal with the battery power issue. The Saint-Jean-sur-Richelieu, Quebec-based company was awarded in October an initial 1.6 million Canadian dollar ($1.5 million) contract to develop a lightweight power source prototype to be worn by Canadian soldiers.

The work will be done with DRDC.

For the first phase, the company will develop a bench-top prototype to test the concept. After that will come a wearable prototype for the soldier and then a production model, said Stephane Oehrli, Rheinmetall Canada’s vice president for electronics systems and air defense.

“We will look at different types of technologies, that include fuel cells, that look at interfacing with [Bionic Power’s] leg,” he said. Small solar panels to be worn by the soldier will also be examined.

The research program is expected to run over the next 42 months.

The goal is to reduce the weight of the power system needed by a soldier to around 2 kilograms.

“Technologies basically exist; it’s how to make them smaller and to work together that we are looking at,” Oehrli said.